The present invention relates generally to a fabrication process of multi-image type hologram and a multi-image type hologram fabricated by that process, and more particularly to a process for the fabrication of a volume hologram with one 3D image changing over to another depending on a viewing direction and a volume hologram fabricated by that process.
Among multi-image type holograms with one image changing over to another depending on a viewing direction, there is a rainbow hologram. With the rainbow hologram, a sort of relief hologram, however, each image can never be set up as a 3D (three-dimensional) one, because available images are of the 2D type.
On the other hand, the process of Patent Publication 1 has been known about how to set up each image in the form of a 3D image. According to this process, a plurality of volume holograms with an object on each image recorded by Denisyuk's method using reference light at a specific angle of incidence are recorded by copying in one single volume hologram.
For that process, however, it is required not only to have a plurality of master volume holograms at the ready, but also to provide strict determination of the angle of incidence of reference light at the time of fabricating those master volume holograms.
When the position of a reconstructed image is located at the surface of a recording material according to Denisyuk's method for fabricating a master hologram in one single stage, on the contrary, it is impossible to fabricate such a multi-image type hologram as described above.
Patent Publication 1
JP-A 10-340038
Patent Publication 2
JP-A 2002-39910
Patent Publication 3
JP-A 2000-214751
Non-Patent Publication 1
“99-3D Image Conference '99”, a CD-ROM version of lecturing monographs (at the Shinjuku schoolhouse, Kogakuin University), an article entitled “Image-type binary CGH by means of EB printing (3)—Enhancement of 3D effect with hidden surface removal and shading—”